The present invention relates to an illumination system that emits a more uniform and intense scattered light and is portable to many applications but preferably used in connection with a scanning operation. In particular, the present invention relates to an integrated chamber illumination system that improves the distribution of emitted light and reduces shadowing by utilizing both direct and diffused light.
For optimal scanning abilities, the surface of the material to be scanned is illuminated to enable the scanning apparatus to clearly read or take a clear picture of the material. Generally, most scanning systems utilize either fiber optics to illuminate the material to be scanned or flood the surface of the material with a halogen or florescent lamp. The fiber optic systems light the surface of the object by shinning light on one end of a fiber optic cable. The light then travels through the fiber optic cable to the opposing end of the cable and emits the light onto the object to be scanned. While this method of scanning has been generally successful, the projected light through a fiber optic cable is not consistently uniform and can therefore be improved upon.
Similarly, the scanning devices that use halogen or florescent lamps to scan the surface of materials flood the surface of the material with light from the halogen or A florescent lamps. This is typically seen in a desktop type scanning application. Again, while these devices have been generally effective for scanning, they can be improved. Those scanning devices that use halogen lamps tend to produce shadowing. Likewise, those devices that utilize florescent lamps have not been designed to take full advantage of the diffused light being emitted from the lamps but allow much of the diffused light emitted from the lamps to be lost to the surrounding environment.
Two types of light are typically used in a scanning system: diffused light and direct light. The direct light provides intensity, while the diffused light provides uniformity. Until now, no scanning system has taken full advantage of the capabilities provided by both types of light to illuminate the surface of an object.
While desktop type scanning systems use both direct light and diffused light by using aperture bulbs, no attempt is made to direct all of the diffused light from the lamps toward the surface to be scanned and therefore, the uniformity of light offered by diffused light is not taken full advantage of.
One system which takes advantage of the uniformity offered by diffused light is a digital camera calibration system that directs light into a white sphere through a pin-point hole in the sphere. Through another opening in the sphere, a camera takes a picture of the white light in the sphere. This picture is subsequently developed to determine whether the pixel within a given array of the camera falls within the specified values. The white color of the interior surface of the sphere reflects the light directed into the sphere in all directions while maintaining the light within the sphere. Thus, a uniform light source is created in the sphere for the calibration process. Because the light in the sphere is uniform, the picture taken by the camera displays each pixel within a given array and the value of the camera can be easily verified.
While the advantages of providing uniform diffused light to create a clear image picture have been recognized and utilized in other applications, such as the digital camera calibration application discussed above, until now, no one has utilized the full capabilities of diffused light to create an extremely uniform illuminating light source. Similarly, no one used the full capabilities of diffused light in connection with a direct light source to create an illumination system which supplies a uniform, high intensity light source with minimal shadowing.
Accordingly, it is the primary object of the present invention to provide an illumination system that emits an extremely uniform amount of light by directing both diffused light and direct light to a central opening in an illumination device.
Still another object of the present invention is to provide an illumination system that reduces light shadowing, outputs more scattered light and increases the obtainable depth-of-field.
Yet another object of the present invention is to provide an illumination system that is small, self-contained and can be used in connection with a variety of applications.
In accordance with these and other objects, the present invention provides an illumination system for emitting a uniform amount of intense scattered light. The illumination system comprises an integrated chamber having a cavity large enough to contain at least two florescent lamps and a reflective interior surface. The chamber is further comprised of a front surface and rear surface. The front surface of the elongated chamber has an elongated opening (i.e. front opening) for emitting the light directed from the florescent lamps and the rear surface has a corresponding elongated opening (i.e. rear opening) aligned with the front opening. This rear opening allows a scanning mechanism, such as a camera, to read information being illuminated through the front opening of the illumination system.
Each florescent lamp positioned within the chamber is coated on its interior with a phosphorous coating, except that during manufacturing a small amount of this phosphorous is removed to create a slot running longitudinally along the florescent bulb that is at least the length of the front opening when the bulb is positioned within the cavity of the chamber. The bulbs are held within the chamber by sockets and positioned such that one bulb is on each side of the front opening. The slot of each bulb is then aligned to direct the light emitted from the slot directly toward the front opening of the chamber.